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Fuel Tank Sealer Botched Job

As some of you know I bought a Yellow 1989 R100RT sight in seen. After replacing just about every seal on the engine and transmission it is now oil tight.
Only problem that I am now faced with is every so often the left Bing carburetor starts to p*#s out fuel. Talked to a mechanic who has been around since JC came to earth and the first question he asked, what was the condition of the fuel tank internally. My response was it appeared that someone tried to coat the internals with POR-15 fuel tank sealer and botched it very badly. The mechanic explained that very fine particles are getting past the in line fuel filters and are either clogging or hanging up on the float needle, thus causing the fuel to overflow. I know I will have to take apart the carbs and ultra sonically clean and rebuild them for a winter project.
Now back to the fuel tank. In your collective minds, how can I strip the POR-15 from the internals of the tank. I placed a flat bladed screw driver down the side and it seems to be able to scrape away very easily, which surprised me. My question is what would work to flush out the tank and reapply the POR-15. I have done a number of tanks with no issues, but I think the PO didn't take the proper time in the preparation, as I know it will take 2 - 3 days to complete the job.
Does anyone have any thoughts?

Tank stripping

There are a couple of methods that you might consider.
if you want to save the paint on the tank, then you might want to try this "old timers" trick. Plug the fuek tap holes and fill the tank with white vinegar. You'll have to let it sit for several days, rotating the tank to get all interior surfaces enough time to let the vinegar do it's stuff.
After a few days, check out the interior and, if it looks good, drain and flush the tank. The vinegar will remove the original liner and, at least soften the POR-15 liner.
It may take more than one treatment in this manner to get all of the old liner out. Then re-line the tank, and you're good.
If you're going to re-paint the tasnk anyway, then just take it to a good radiator shop and have then "tank" it. That will remove everything, including the paint. Now you get to start from scratch!

There are a couple of methods that you might consider.
if you want to save the paint on the tank, then you might want to try this "old timers" trick. Plug the fuek tap holes and fill the tank with white vinegar. You'll have to let it sit for several days, rotating the tank to get all interior surfaces enough time to let the vinegar do it's stuff.
After a few days, check out the interior and, if it looks good, drain and flush the tank. The vinegar will remove the original liner and, at least soften the POR-15 liner.
It may take more than one treatment in this manner to get all of the old liner out. Then re-line the tank, and you're good.
If you're going to re-paint the tasnk anyway, then just take it to a good radiator shop and have then "tank" it. That will remove everything, including the paint. Now you get to start from scratch!

Great Idea, as this is less toxic than using an acid. Thank you. Will get going this weekend and will try to remember to take pictures and report back to this board.

Is there a lot of junk floating around, and can you see evidence in the carbs themselves?

You could go to any auto parts store and stick an inline fuel filter in each line to see what you get. Many airhead owners have done this as the original lining starts to deteriorate.

Also, bear in mind that if some previous owner used POR-15, they probably did it for a reason, whether it was botched or not. Getting all the POR-15 out of there will likely just be the start of fixing your fuel issues.

Sometimes floats just stick on these old bikes as well. It's why many of us just shut the gas off when we stop.

Vinegar is an acid, albeit a weak one, and I don't think I'd care to subject the innards of my fuel tank to a thorough soaking in it. Too many crevices that might not be well flushed and then sealed over when the new coating was applied, and any residual "rust haze" will impair the adhesion of the new coating.

POR-15 does not use an acid. It uses methlyene choride, the same compound found in most commercial paint strippers.

I'd use POR and take the requisite time to do the job right. It's a bitch, timewise, but it's a good product. Just make sure to protect the exterior finish, if that's an issue.

"It is what you discover, after you know it all, that counts." _ John WoodenLew Morris
1973 R75/5 - original owner
1963 Dnepr

Vinegar is an acid, albeit a weak one, and I don't think I'd care to subject the innards of my fuel tank to a thorough soaking in it. Too many crevices that might not be well flushed and then sealed over when the new coating was applied, and any residual "rust haze" will impair the adhesion of the new coating.

POR-15 does not use an acid. It uses methlyene choride, the same compound found in most commercial paint strippers.

I'd use POR and take the requisite time to do the job right. It's a bitch, timewise, but it's a good product. Just make sure to protect the exterior finish, if that's an issue.

Lew,

Totally agree, as this product only works when it's properly prepared.

If you don't want to pay the bucks for POR's stripper, you can always pick up some Dad's' at a hardware store, it contains methylene chloride (as does POR) and it's cheaper per quantity.

ACE hardware offers a similar product under their label that is just as good.

An old stand-by, Strypeeze... killer stuff, killer ingredients. Get this stuff on you and you'll know it pronto.

3M Safest Stripper is touted as containing no methylene chloride, and cleans up with water.... never used it myself, but most 3M product, in my experience, get the job done. Still.... it needs water to clean up.

Wear nitrile gloves, eye protection, and provide plenty of ventilation while using any of these products.

"It is what you discover, after you know it all, that counts." _ John WoodenLew Morris
1973 R75/5 - original owner
1963 Dnepr

Not to dissuade you (or anyone else) from going the POR-15 liner route, but the primary reason for my use of Red Kote when coating the fuel tank was the ability to remove the coating. Red Kote dissolves in MEK or acetone. Being some what of a perfectionist on occasion, I liked to have that ability. POR-15, however, is not so easy to remove.

Adding methylene chloride paint stripper and sealing the tank is one route. The POR will need to be flushed out of the fuel nipples along with the paint stripper - probably by using paint thinner. Putting in a gallon (or so) of of super clean (5% sodium hydroxide) in the tank afterward will help. The superclean can be removed with water and the tank flushed. Neither product will damage the tank metal, but will completely ruin the tank paint. But then, all tank coatings and cleaners ruin paint.

I bought some rubber stoppers from the hardware store to plug the fuel valve nipples. Some plastic wrap and rubber bands can seal the cap opening. The next major items are goggles, old clothes, disposable shoes, gloves, patience, and some tenacity. Good luck!

Not to dissuade you (or anyone else) from going the POR-15 liner route, but the primary reason for my use of Red Kote when coating the fuel tank was the ability to remove the coating. Red Kote dissolves in MEK or acetone. Being some what of a perfectionist on occasion, I liked to have that ability. POR-15, however, is not so easy to remove.

Adding methylene chloride paint stripper and sealing the tank is one route. The POR will need to be flushed out of the fuel nipples along with the paint stripper - probably by using paint thinner. Putting in a gallon (or so) of of super clean (5% sodium hydroxide) in the tank afterward will help. The superclean can be removed with water and the tank flushed. Neither product will damage the tank metal, but will completely ruin the tank paint. But then, all tank coatings and cleaners ruin paint.

I bought some rubber stoppers from the hardware store to plug the fuel valve nipples. Some plastic wrap and rubber bands can seal the cap opening. The next major items are goggles, old clothes, disposable shoes, gloves, patience, and some tenacity. Good luck!

Hi Stan,

I liked to have that ability. POR-15, however, is not so easy to remove.
That is a huge understatement, however did call the 800 # and spoke to a gentleman by the name of Matt and was advised of the following:
POR-15 can be removed using the following chemicals:
1. Methylene Chloride
2. My Stripper
3. Air Craft paint Stripper.
All of the above are nasty stuff and to be handled with care.
Wish there was a way to do this simply and not destroy the paint?